JPH071037B2 - Self-priming vertical pump on the suction side - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a suction side self-priming vertical shaft pump, and more specifically, it is a small pump with a power of about 0.1 to 1 kw, and at a high head, a specific speed. The present invention relates to a technique for reducing internal fluid loss of a pump having a small N _SQ .

[Conventional technology]

The suction side self-priming vertical shaft pump has a structure in which the inlet of the impeller chamber that houses the centrifugal impeller is arranged upward, and the suction side self-priming chamber that communicates with the upper part of this impeller chamber through the inlet. Is provided, the suction port of the pump is formed in the upper part of the suction side self-suction chamber, the discharge flow path communicating with the outlet of the impeller chamber is provided upward, and the discharge port of the pump is formed at the upper end thereof. .

The principle of operation of the suction side self-priming vertical shaft pump is as follows:
Since it is explained in detail in No. 163007, its explanation is omitted here. This document introduces JP-A-56-110593 and JP-A-56-165996 as prior arts of a suction side self-priming vertical shaft pump.

However, in the pumps having the structures shown in these documents, the partition that divides the suction side self-suction chamber and the impeller chamber becomes an integral structure with the casing, which makes modeling difficult, and the shape of the impeller chamber and its surroundings is the pump. It is unsuitable for improving the characteristics, and in particular, the internal fluid loss of a pump having a small specific speed must be increased. Therefore, there are a first conventional example and a second conventional example in which a partition plate or the like is adopted to rationalize the shape of the impeller chamber and its surroundings.

FIG. 4 is a sectional view of the first conventional example, and FIG. 5 is VV of FIG.
FIG. 6 is a sectional view, FIG. 6 is a sectional view of a second conventional example, and FIG. 7 is a sectional view taken along line VII-VII of FIG.

The suction side self-priming type vertical shaft pump shown in FIGS. 4 and 5 is provided with a stepped portion 4 at a lower end portion of a casing 3 in which a suction side self-priming chamber 1 and a discharge passage 2 are integrally formed. A partition plate 7 having an inlet 6 for a centrifugal impeller 5 is fitted to the stepped portion 4, and a vortex winding chamber 8 surrounded by the lower end portion of the partition plate 7 is formed below the partition plate 7. The outlet 9 of the winding chamber 8 and the discharge passage 2 are communicated with each other by a square hole-shaped communication passage 10 provided in the partition plate 7. Of course, the outlet 9, the communication passage 10 and the discharge flow passage 2 are continuously and smoothly communicated with each other so that there is no sudden change in the cross section of the flow.

The impeller 5 housed in the spiral chamber 8 is supported by a bearing 11 and fixed to a shaft 13 of a drive machine (not shown) which penetrates the shaft sealing device 12 with a screw 14. The partition plate 7 is tightened by a countersunk screw (not shown) on the partial projection 1a toward the inside of the suction side self-suction chamber 1, and is fitted and abuts on the stepped portion 4. The vortex chamber 8 is closed by fixing the bottom plate 17 to the lower end surface of the casing 3 via the packing 16 with the screw 18 screwed into the screw hole 18a of the casing. The hole 17a provided in the bottom plate 17 is for pump installation.

The suction port 19 of the pump is provided at the upper part of the suction side self-suction chamber 1.
By providing the discharge ports 20 of the pump at the upper end of the discharge flow path 2, the suction side self-priming vertical shaft pump as described at the beginning is constructed.

In the first conventional example, the partition plate 7 is separated from the casing 3 and fitted to the stepped portion 4 which is accurately concentric with the shaft 13 as a mutually machined fitting portion. The spiral chamber 8 formed by being surrounded by the lower end of the
Therefore, the spiral chamber 8 having the exact same center with respect to the impeller 5 is formed, and the characteristics can be easily maintained.

By the way, the width (measured in the axial direction) of the impeller 5 of the impeller 5 of the pump having a high lift and a small specific speed, which is a field of application of the present invention, is naturally small, so that the width of the spiral chamber 8 is also small. The cross-sectional area (measured in the direction of flow, that is, the circumferential direction) cannot be taken large, the flow velocity becomes large, and the fluid loss proportional to its square becomes large. Therefore, as is often done, in addition to making the lower and upper both surfaces of the spiral chamber slanted, that is, on the same radius, the cross section of the spiral chamber has a width that increases as the diameter increases, and it also has an endless shape. Since there is a limit to the angle of this divergent shape, the plane projection figure of the spiral chamber itself is made large so that the cross sectional area of the spiral chamber is made large.

However, enlarging the plane projection figure of the spiral chamber is limited because the dimension B of the end point of the spiral chamber shown in FIG. 5 becomes small. In order to overcome the limit dimension B determined by the minimum wall thickness of casting, the outer diameter of the partition plate 7 in which the spiral chamber 8 is formed, that is, the inner diameter of the stepped portion 4 is increased, and the effective width of the packing 16 is increased. Therefore, the outer diameter of the lower end portion of the casing 3 must be increased.

Increasing the outer diameter of the casing 3 undesirably increases the installation size of the pump. Further, the range in which only the spiral chamber 8, that is, the partition plate 7 can be changed to meet various required pump characteristics becomes small, the mold of the casing 3 is changed, and it is not preferable in terms of standardization and productivity. Therefore, there is a second conventional example in which the cross-section of the vortex winding chamber is enlarged within the limited outer diameter dimension of the partition plate 7 to accommodate a pump having a large specific speed.

In the second conventional example shown in FIGS. 6 and 7, the parts having the same reference numerals as those in FIGS. 4 and 5 have approximately the same function. In the drawings, reference numerals are given only to the essential parts of such a thing, the explanation is omitted, and only different parts are explained.

An inner wall 63 of the spiral winding box at the beginning of winding of the spiral chamber 62 is provided at the lower end of the partition plate 61 having the communication passage 10 in the shape of a square hole so that there is no sudden change in the cross section of the discharge flow path 2. The inner wall 63 of the spiral winding box at the winding start portion is smoothly connected to the impeller inner wall 65 of the impeller chamber 64 surrounded by the lower end of the casing 3 and having the same inner diameter as the outer diameter of the partition plate 61.

In this way, the spiral chamber 62 is composed of the spiral wound box inner wall 63 and the portion of the circular impeller chamber 64, which is not a complete spiral chamber, but the impeller chamber 64 has a stepped portion. Partition plate with 4
The inner surface (the inner wall 65 of the impeller) is smooth because it is formed by fitting, for example, by machining, so that good characteristics are exhibited as a whole. Therefore, the inner wall of the spiral box 63
Alternatively, a circular casing may be used for a so-called small-sized pump that includes only the impeller chamber 64 over the entire circumference.

The second conventional example uses the impeller chamber 64 to make the spiral chamber 62
The cross-sectional area in the circumferential direction is expanded to expand the range applicable to a pump with a small specific speed, but from the outlet 66 of the impeller chamber 64, which is the end point of the spiral chamber 62, to the communication passage 10, as shown in the figure, A large reduction in cross section remains.

[Problems to be Solved by the Invention]

In the first conventional example and the second conventional example in the above-mentioned conventional technique, since the spiral chamber 8 or 62 is separated from the casing 3 having a large shape, the shape of the spiral chamber and the concentricity with respect to the impeller are accurately maintained. The velocity characteristics of the fluid flowing out from the outer diameter of the impeller are effectively converted into pressure energy, and the pump characteristics are good. Especially, the effect is great for a small and high head with a small specific speed.

However, in the first conventional example, the size B of the end point of the spiral chamber 8 is limited, and therefore, in order to increase the size of the thin spiral chamber in accordance with the required pump characteristics, the outer diameter of the casing 3 must be increased. Not only does it affect the installation area, but it also requires new molds and reduces productivity in terms of standardization.

In the second conventional example, the size B is overcome, and the spiral chamber 62 is
However, there is a sharp reduction in cross section between the outlet 66 of the impeller chamber and the communication passage 10, which causes a decrease in pump efficiency due to an increase in fluid loss.

The object of the present invention is to increase the cross-sectional area of the vortex chamber without increasing the outer diameter of the casing and suppress the increase of fluid loss near the outlet of the impeller chamber to improve the efficiency of the pump. The purpose of the present invention is to provide a vertical shaft pump.

[Means for Solving the Problems]

The suction side self-priming vertical shaft pump according to the first aspect of the present invention is provided with a stepped portion at a lower end portion of a casing integrally formed with a suction side self-priming chamber and a discharge flow passage, and the stepped portion is provided with a centrifugal impeller. A partition plate having an inlet for is fitted to form an impeller chamber surrounded by the lower end portion of the casing on the lower side thereof, and the outlet of the impeller chamber and the discharge flow path are formed on the partition plate. In a suction side self-priming type vertical shaft pump that communicates with a provided communication passage, the communication passage is opened toward the outer periphery of the partition plate, and an outer inner wall of the discharge flow passage and an outlet inner wall of the impeller chamber are formed. It is made continuous by a line at the same position as or more than the outer diameter of the partition plate.

In the suction side self-priming vertical shaft pump of the second invention, in the first invention, a spirally wound chamber is formed by the spirally wound inner wall and the impeller inner wall protruding below the partition plate. And the outlet of the impeller chamber is formed at the end of the spiral chamber.

[Action]

In the first aspect of the invention, the width of the impeller and hence the width of the spiral chamber (both measured in the axial direction) is small and the cross-sectional area of the spiral chamber (measured in the circumferential direction) is large because of the high head and small specific speed. Even when it is difficult to remove, the impeller chamber at the lower end of the casing is used as a spiral winding chamber to secure a sufficient cross sectional area of the spiral winding chamber without increasing the outer shape of the casing, that is, the installation area of the pump. Can be maintained. In particular, the outlet of the impeller chamber, the communication passage, and the discharge passage are connected by a smooth line with no sudden changes in cross section, which significantly reduces the fluid loss.
Pump efficiency is further improved.

In the second aspect of the invention, in addition to the above-mentioned action, the spirally wound chamber inner wall provided at the lower end portion of the partition plate is connected to the impeller chamber inner wall to form a spirally wound chamber. Pump efficiency is improved.

〔Example〕

1 is a sectional view of the embodiment, FIG. 2 is a partial sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a partial sectional view corresponding to FIG. 2 of a different embodiment.

In FIG. 1 and FIG. 2, the same reference numerals as those in FIGS. 4 and 5 have approximately the same functions. That is, the casing 31 in which the suction side self-suction chamber 1 and the discharge flow path 2 are integrally formed
A stepped portion 4 is provided at the lower end portion of the, and a partition plate 32 having an inlet 6 for a centrifugal impeller 5 is fitted to the stepped portion 4 (the casing 31 and the partition plate 32 have a characteristic structure). Have more later). The impeller 5 is fixed to a shaft 13 having a bearing 11 and a shaft sealing device 12 with a screw 14, and a partition plate 32 is a countersunk screw to the suction side self-suction chamber 1
Bottom plate 17 which has a hole 17a for installation through a packing 16 at the lower end surface of the casing 31 and is fastened to the partial projection 1a inward of
Are fixed by screws 18 and screw holes 18a. A suction port 19 is provided at the upper part of the suction side self-suction chamber 1, and a discharge port is provided at the upper end of the discharge flow path 2.
20 are provided.

Next, the characteristic structure of this embodiment and its periphery will be described. At the lower end of the partition plate 32, an inner wall 34 of the vortex winding box at the beginning of winding of the vortex winding chamber 33 is provided. This spiral box inner wall 34
Is smoothly connected to an impeller inner wall 36, which is surrounded by the lower end portion of the casing 31 and has the same inner diameter as the outer diameter of the partition plate 32, such as a machined impeller inner wall 35. After all, the spiral chamber
33 is composed of a spiral box inner wall 34 and an impeller inner wall 36.

The outlet inner wall 33 of the outlet 37 of the impeller chamber 35, which is the end point of the spiral chamber 33, and the outer inner wall 2a of the discharge passage 2 provided in the casing 31.
And are continuous with each other as shown by a smooth line due to the molding of the casing 31. The position of this line is the same as or larger than the outer diameter of the partition plate 32. On the other hand, a communication path 39 is opened in the partition plate 32 toward the outer periphery. Note that theoretically, the line connecting the outer inner wall 2a and the inner outlet may be the same as the outer diameter of the partition plate 32, but if it is slightly inward due to an error such as casting or die-casing, the stepped portion will be processed. Although a slight disconnection of the line occurs, it is smaller than the cross-sectional change in FIG. 6 and there is no large deterioration in characteristics, but it is better to position it outside with a margin. At that time, the range is set so as not to be too large and hinder the liquid tightness of the packing 16.

According to such a structure, the limit dimension B shown in FIG. 5 of the conventional example does not exist, the impeller inner wall 36 is utilized to enlarge the spiral chamber 33, and the end point of the spiral chamber 33 is used. The outlet 37 of the impeller chamber 35, the communication passage 39, and the discharge flow path 2 are connected to each other by a smooth line without a sudden change in cross section, and fluid loss is reduced. Experiments show that this reduction in fluid loss is significant.

In a different embodiment shown in FIG. 3, the communication passage 39 provided in the partition plate has a round shape and a part of the circumference thereof opens toward the outer circumference, and the impeller chamber 35 is close to the outlet 37 and is machined or the like. A partial spiral box inner wall 36a formed by casting or the like, which is further displaced from the impeller inner wall 36 formed by. The screw hole 18a for attaching the bottom plate is the inner wall 3
6a and the outlet inner wall 38 are arranged so as to avoid liquid tightness of the packing.

Either embodiment may have a so-called circular casing without the inner wall 34 of the spiral box or a partial spiral wall inner wall 36a close to this.

〔The invention's effect〕

The suction side self-priming vertical shaft pump according to the first aspect of the present invention is provided with a stepped portion at a lower end portion of a casing integrally formed with a suction side self-priming chamber and a discharge flow passage, and the stepped portion is provided with a centrifugal impeller. A partition plate having an inlet for is fitted to form an impeller chamber surrounded by the lower end portion of the casing on the lower side thereof, and the outlet of the impeller chamber and the discharge flow path are formed on the partition plate. In a suction side self-priming type vertical shaft pump that communicates with a provided communication passage, the communication passage is opened toward the outer periphery of the partition plate, and an outer inner wall of the discharge flow passage and an outlet inner wall of the impeller chamber are formed. Since it is made continuous with a line located at the same position as or larger than the outer diameter of the partition plate, the cross-sectional area of the spiral chamber is expanded to the impeller chamber, and the efficiency of the high-lift pump with a small specific speed is improved. , The impeller chamber outlet, the partition plate communication path and the discharge flow path show sudden changes in cross section. Ku, has the effect of fluid loss is significantly reduced, an effect of suppressing expansion of the installation area.

In the second aspect of the invention, the spirally wound chamber wall and the impeller chamber inner wall that project further below the partition plate form a spiral spiral chamber, and at the end of the spiral chamber, the spiral chamber is formed. Since the outlet is formed, there is an effect that the speed head generated by the impeller is effectively converted into a pressure head and the pump efficiency is further improved while maintaining the above effect.

[Brief description of drawings]

1 is a sectional view of the embodiment, FIG. 2 is a partial sectional view taken along line II-II of FIG. 1, FIG. 3 is a partial sectional view corresponding to FIG. 2 of a different embodiment, and FIG. FIG. 5 is a sectional view of the first conventional example, and FIG.
FIG. 6 is a sectional view taken along line VV of FIG. 4, FIG. 6 is a sectional view of the second conventional example, and FIG. 7 is a sectional view taken along line VII-VII of FIG. 2 ... Discharge passage, 3,31 ... Casing, 4 ... Stepped portion,
5: Impeller, 7,32,61 ... Partition plate, 8,33,62 ... Whirlpool chamber, 9,37,66 ... Exit, 10,39 ... Communication passage, 17 ... Bottom plate,
34,63 …… Swirl box inner wall, 35,64 …… Impeller room, 36,65…
… The inner wall of the impeller, 38 …… the inner wall of the exit.

Claims (2)

[Claims] 1. A stepped portion is provided at a lower end portion of a casing integrally formed with a suction side self-suction chamber and a discharge flow passage, and a partition plate having an inlet for a centrifugal impeller is fitted to the stepped portion. The suction side self-priming is formed underneath by forming an impeller chamber surrounded by the lower end portion of the casing, and communicating the outlet of the impeller chamber and the discharge flow path with a communication passage provided in the partition plate. In the vertical type vertical pump, the communication passage is opened toward the outer periphery of the partition plate, and the outer inner wall of the discharge flow path and the inner outlet wall of the impeller chamber are equal to or more than the outer diameter of the partition plate. A self-priming vertical pump on the suction side, characterized by being continuous with the line at the position. 2. The suction side self-priming type vertical shaft pump according to claim 1, wherein the spirally wound inner wall and the impeller inner wall that project below the partition plate form a spirally wound spirally wound chamber. A suction side self-priming vertical shaft pump, characterized in that the outlet of the impeller chamber is formed at the end of the spiral chamber.